TAPPI T839 Edge Compression Test (ECT) – Clamp Method

TAPPI T839 – Edgewise Compressive Strength of Corrugated Fiberboard Clamp Method (Short Column Test).

The test is conducted using a universal testing machine with a compression platen that applies a load perpendicular to the edge of the corrugated board sample. The sample is placed in a clamp fixture that keeps the edges of the sample perpendicular to the applied load during testing. The test is performed on a single sheet of corrugated board or a sandwich panel with two outer linerboard sheets and a corrugated medium between them. The corrugated medium can be of different flute types, such as A, B, C, or E flute. During the test, the sample is compressed at a constant rate until it reaches a predetermined failure criterion, such as a certain percentage of deformation or load drop. The maximum load sustained by the sample is recorded, and the edge compression strength (ECT) is calculated as the maximum load divided by the width of the sample.

The ECT value is a measure of the stacking strength of a corrugated structure. It reflects the ability of a box to resist crushing and maintain its shape when subjected to compressive forces during storage and transportation. The TAPPI T839 standard for Edge Compression Test (ECT) – Clamp Method provides detailed procedures for conducting the test, including sample preparation, clamping, and testing conditions. It is widely used in the paper and packaging industry to ensure the quality and performance of corrugated fiberboard products. Data collected can be used along with flexural stiffness and box dimensions to accurately predict the overall top to bottom compression strength of corrugated boxes. Utilizing a clamp fixture reduces the potential of edge rolling of the linerboards during testing. The max force to cause compressive failure is recorded as the ECT value.